Heterocyclic sulfonamides and method of preparing the same



Patented July 15, 1952 TAT HE'rEaocYoLro SULFONAMIDES'AND f f I METHOD OF PREPARING THE SAME James W. Clam), Darien, and Richard 0. mus, fl Jr., Riverside, Conn., assignors to American- Cyanamid Company, New York, N. Y.,a corporation of Maine No Drawing. Application April 4-, 1950,

Serial No. 153,998

I g 12 Claims. (01. 260-309) This invention relates toheterocyclic sulfonamides and methods of preparing the same. More particularly, itrelates to imidazole and benzimidazole sulfonamides and their preparation. 7

It is generally recognized that numerous func-' tions and actions of the human body are largely controlled by a wide varietyof enzymes. One of these numerous v enzymes is calledcarbonic anhydrase because 'it is involved in the metabolism of carbon dioxide. This, enzyme has other functions too, since it can catalyze the conversion of carbon dioxide to carbonicacid. The excretion of acid by the kidneys is thought to be due to this function of carbonic anhydrase.

The excretion of acid by the kidneys is one method by which thebody normally conserves salt. The maintenanceof a constant ratio of salt to water in the body is of utmost importance for general health.-. In some cases however, excess salt and water accumulate in the tissues causing a condition which is called edema. It is frequently encountered-in association with congestive heart failure. The excess. salt and water cause an uncomfortable swelling of the tissues and place an. added strain on the heart; To combat this condition so-calleddiuretic agents are sometimes used to promote the excretion of the excess salt and water, These agents, for the most part, in the past,have been mercury derivatives, Since these compounds contain mercury, they are -not'without-toxicity on continued use, and must be administered by injection.

Shortly after sulfanilamide came into *wide spread use',-Mann and Keilin, Nature, 146, 164 (1940) foundthat-iinbut none of the other sulfa drugs, specifically inhibit the enzyme carbonic anhydrase. Within: the past year or two sulfamilamide was experimentally used in several cases of congestive heart failure. While the sulfanilamide. helped to promote the excretion of excess salt and water, it was not sufficiently active to be safely administered in adequate doses.

I We have" now found that certain new heterocyclic sulfonamides show much greater activity than sulfanilamide in inhibiting carbonic anhydrase. These compounds may be illustrated by the following general formula:

or a benzimidazole nucleus in which one or more of the hydrogen atoms may be substituted by any of theiollowing groups alkyl, alkaryl or aryl. I 1

The compounds are, in general, jwhitecrys- .talline solids having definite melting points and being soluble in water. The compounds of the present invention are prepared by dissolving. the 2-mercaptoimidazole or 2-mercaptobenzimidazole in an aqueous acid solution and passing in chlorine gas to produce the correspondingsulfonyl chloride. This prodnot is then treated with an excess of ammonia in the form of liquid ammonia or anmionium hydroxide to produce the unsubstituted "sul'fonamides and with a'n'alkylamine or an arylamine to produce compounds substituted on th"sulfonamide group. i i The reaction time 'is' not too critical but 'chlo rine should be added at such a ratethat the temperature does not'rise excessivelyanduntil an excess is present in the reaction mixture. The temperature during the chlorination is' preferwithin the range of -'10 C. to

ably maintaine 25 C. y o 1 I I The compoundsfwe're found to beeffective carbonic anhydrase inhibitors and as such, j may prove valuable in the treatment of infections, in the relief of edemaassociated with congestive heart failure or in other conditions where inhibition of carbonic anhydraseis useful.

The following examples illustrate the preparation of representativesimidazole'- suli'ona'mides and benzimidazole sulfona rnides from the corresponding 29-mercaptoimidazole or 2-mercapto- ,benzimidazole- All parts-are by weight unless otherwise indicated. i

. 2'-imidazo'l esulfonamide 1' i One part of 2-mercaptoimidazole is mixedwith 10 parts oi 1 N hydrochloric acid andthe ,mixture is stirred in a cooling bathwhile chlorine is passed in through a capillary tube until the color of excess dissolved chlorine appears in the mixture. About 70 minutes is required. The temperature of the mixture is'k'ept-below 10 C. and

preferably below 5 Ctto avoid'excessive decomposition of the unstable; sulfonylchloride. The

; Example 1, except that of theory based on mercapto crude 2-imidazolesulfonyl chloride is filtered and washed with ice-cold water. It can be recrystallized from. ether; the pure compound melts at 183 0., with bubbling.

The crude damp,2-imidazolesulfonyl chloride is added gradually to a large excess (35 parts) of liquid ammonia. After about fifteen minutes, the excess ammonia is allowed to a the residue istaken up in a small amount of. di lute ammonium hydroxide. The extract is treat-- ed with activated charcoal, filtered, and the filtrate is neutralized with acid; 'withchilling The mixture'is evaporated to dryness and the residue is recrystallized from a little water. The product is obtained as a white crystalline solid,

melting point, 236-2365? 0., with decomposition.

EX M LE 2 1-methyl-2-imidazolesulfonamide ride by recrystallization from ethyl acetate. .The pure 1-methyl'-2 imidazolesulfonamide is a, white crystalline solid, melting point lfl8 .5-I49.5 c.

j '1 pi ienyl-Z-imidazdesulfonamide In'another procedure following the method of Example 1,1.5 parts of Z-mercapto-l-phenylimidazole and 20 parts of 1N hydrochloric acid are used, and chlorine ispassed'in for twenty-five minutes. The end of the reaction is judged by a fall in temperature as well as by the, appear- 'ance of the color of dissolved chlorine. I The crude damp l-phenyl-2-imidazolesulfonyl chloride is converted to the sulfonamide with liquid ammonia by the method of Example 1- An excess of dilute ammonium hydroxide is required to extract the product from an insoluble fraction. The product isthen'precipitated with acid, filtered, and recrystallized from water. It is obtained as a .white crystalline solid, 170- 170.5 C. The yield is 74% on the mercapto compound. 1

Z-benimzdazolesuljonamide of theory based 2-mercaptobenzimidazole is converted to the corresponding'sulfonyl chloride by the method'of to 2.5 parts of mercapto compound) is .used as a reaction medium, and'chlorine ispassed in for fifty minutes. The crude i is converted to the sulfonamide with liquid'am- 1 monia by the method. product is recrystallized 'from water; The pure described above.

compound is a white.

crystalline solid, melting point, 214? Q, with bubbling. The yield was 43% compound. 2-intidazolesuZfondi-n-butyldmide acetic acid 100 parts The evaporate and line. solid, melting point, 176-177 C.

. the alcoholic mother 'liquors.

melting point 4 of 3.9 parts of di-n-butylamine in 5 parts of dry pyridine. The mixture is stirred for two hours and diluted with 25 parts of water. The solid is filtered, washed, and recrystallized several times froin ethanol, withathe use of activated charcoal; Dilution of the alcoholic mother liquors with water permits recovery of additional product. The pure compound is a white crystal I EXAMPLE 6 '2-i1i ictaeo[esuBfon-P- 7 2-imidazolesullonyl chloride is prepared 'as described in: Example 1.- 2.5 parts of crude dried 2-imidazolesulfonyl chloride are added gradually toastirred solution of 2.6 parts of p-toluidine in 3 parts of dry pyridine, with chilling. The mixture is stirred for one hour with chilling and then for one hour without chilling. 25 parts of I water are added, and the solid is filtered.- It is extracted withv dilute alkaltkfiltered and the filtrate acidified to precipitate the product... After a second extraction with alkali and reprecipita tion' with acid, the pro duct is recrystallized from ethanol, with the'usfe of activated. charcoal- Ad.- ditional pro ducti can. .be recovered by dilution of with water. The pure compound is a white crystallmefsolid,,melt

ing point 20s-20.9- o; The yield of pureproduct was 20 of theory based on mercapto-compound.

We claim;

1. Compounds of the grou'p consisting of da a having the generalformula: is

p X- SOzNRRJ. in which R and R are membersof the group consisting of hydrogen,lowe'r alkyl and a monocyclic aromatic hydrocarbon radical and); is'a' hetero cyclic radical of "the group, consisting oif2 imidazoleand 2 benzimida'zoleiradicals.

2. 2-imidazolesulfonamide.

3. l-methyl-2-imidazolesulfonamide.

4. 1-phenyl-2 imid'azolesulfonamide,

5. 2-benzimidazolesulfonamide.

6. 2-imidazolesulfondi-n-butylamide.' f e 7. A method of preparing compounds having the general formula:

. o X so'2NRR' in which Rand R are members of the group consisting of'hydrogen, lower alkyl and a monocyclic aromatic hydrocarbon radical and-X is a hetero- 7 cyclic radical of the-group consisting of 2 hydrocarbon amine; damp sulfonyl chloride Followingthemethod described inJExampl I;

' 1 2.5 partsjof dridrrcnid 2-imidazolesulf oriyl .3 I chloride arer addedgradually'tofa stirred solution imidazole and 2 benzimidazole ra'dicals which comprises reacting a member-of the group consisting of 2 mercaptoimidazole and 2 mercapto- 'benzimidazole with chlorine in'the presence of an aqueous acid solution and "subsequently -With' a member of the group consisting of ammonia, a lower alkyl amine and a monocyclic aromatic s. A method of preparing 2-imidazolesu1fon amides which comprises dissolving 2-mercaptoimidazole .in aqueous" acid: soIutiOnQ'passing chlorine into'said solution; mixing the resulting product with'liquid ammonia and'rcovering said.

2-imidazolesulfonamide therefrom.

9. A method ofnpli aringrr-methyl 2 imidazolesulfonamide which comprises dissolving 2? mercapto-l methyl imidazole in .an aqueouslh'y} drochloric acid solution, passing chlorine into said solution, mixing the resulting product with liquid ammonia and recovering said l-methy'l-z imidazolesulfonamide therefrom. I

0. A. method of preparing 1-phenyl-2-imid- 5 azolesulfonamide which comprises dissolving 2- mercapto-l-phenyl imidazole in an aqueous hydrochloric acid solution, passing chlorine into said solution, treating the reaction product thus obtained with liquid ammonia and recovering said 1-phenyl-2-imidazolesulfonamide therefrom.

11. A method of preparing 2-benzimidazolesulfonamide which comprises dissolving 2-mercaptobenzimidazole in an aqueous acetic. acid solution; passing chlorine into said solution, mixing the reaction product thus obtained with liquid ammonia and recovering said 2-benzimidazolesulfonamide therefrom.

12. A method of preparing Z-imidazolesulfondin-butylamide which comprises dissolving 2- mercaptoimidazole in an aqueous hydrochloric acid solution, passing chlorine into said solution, mixing the reaction product thus obtained with di-n-butylamine and recovering said Z-imidazolesulfondi-n-butylamide therefrom.

JAMES W. CLAPP. RICHARD O. ROBLIN, J R.

REFERENCES CITED The following references are of record in th file of this patent:

Name Date 2,410,620 Allen et a1 Nov. 5, 1946 

1. A COMPOUNDS OF THE GROUP CONSISTING OF THOSE HAVING THE GENERAL FORMULA: 